1. Field of the Invention
The present invention relates to telecommunications and, more particularly, to the establishment of dial-up data sessions, such as between a wireless user terminal and a remote access server.
2. Description of Related Art
The explosive growth of telecommunications has ushered in a new era of convenience and productivity. Users are now commonly able to establish data sessions with remote computers via dial-up access over a telephone circuit. For instance, a user can operate a local computer equipped with a modem to place a telephone call to a remote computer equipped with a modem. When the remote modem answers the call, the remote modem and local modem can agree on a communication protocol and then begin to exchange useful data.
One of the most common applications of dial-up data service is to provide remote access to a network, such as a corporate network or the Internet, for example. In this arrangement, the remote computer/modem is typically a remote access server (also known as a “network access server”). The remote access server may sit as a node on the network and include one or more modems for receiving dial-up data calls from user terminals. When a user operates a local terminal to establish a dial-up data connection with the remote access server, the user may then be able to access resources on the network, such as e-mail and file services for instance.
The advent of wireless telecommunications, such as cellular telephony, has extended the availability of dial-up data access. Just as a user can operate a cellular telephone or other mobile station to place a voice call to virtually any telephone number, a user can operate a suitably equipped mobile station to place a dial-up data call to virtually any remote computer.
In typical operation, a user terminal such as a notebook computer or personal digital assistant (“PDA”) can be connected to or otherwise equipped with a wireless modem or can include a modem and be coupled or otherwise equipped with a mobile station for placing wireless telephone calls. A user can then operate the terminal to place a wireless dial-up data call to a remote computer/modem.
In a cellular telephone system, each cell is defined by a radiation pattern from a respective base station antenna. The base station is then coupled or equipped with a switch or other gateway, which provides connectivity with a transport network such as the public switched telephone network (“PSTN”) for instance. A wireless user terminal operating in a cell can thereby communicate with the base station over a radio frequency air interface, and communications can then be carried via the PSTN to virtually any remote communication terminal.
Thus, to place a dial-up data call from a wireless user terminal equipped with a modem, a user can instruct the terminal to call a telephone number of a remote computer equipped with a modem. The wireless terminal would then initiate a telephone call to that number via the air interface and switch. Once the remote modem answers the call, the two ends can agree on a communication protocol and then begin to exchange data.